The present invention relates to bed frames, and, more particularly, to a bed frame made up of T-shaped side rails.
In general, bed frames are comprised of a pair of side rails and a plurality of cross rails that span between the side rails in order to assemble and complete the bed frame structure. The bed frame, once assembled is adapted to support a box spring and a mattress to make up the bed itself. Normally, therefore, the conventional bed frame assembly is shipped and delivered unassembled for convenience and general transportation and the two side rails are L-shaped steel members.
One type of bed frame is the adjustable width folding frame and, in that bed frame, the cross rails are formed of cross rail members that are pivotally affixed at or near each end of the side rails. For delivery to a customer, the cross rail members are interfitted with and parallel to the side rails for ease of packing and shipment. In the assembly of the bed frame at the location of the customer, therefore, the cross rail members are pivoted about 90 degrees so as to extend generally at a right angle from the side rails and the opposite, free ends of the cross rail members are affixed together at the center area of the bed frame to form cross rails that thus span between each of the side rails. As such, when so assembled and affixed together, the bed frame assumes a generally rectangular configuration to accept the box spring and the mattress.
There is also, normally, a center beam that is positioned so as to be generally parallel to the side rails and which is located at or near the center of the bed frame in order to provide additional support to the overall structure and, of course to the box spring and mattress. The center beam is added to the bed frame to span between the cross rails in order to prevent the further relative movement between the cross rail members as well as to secure the center beam into the bed frame to finalize the task of assembling that bed frame.
Another type of typical bed frame is the fixed width drop together bed frame where the cross members are fixed in length and there are female sockets formed at or near the ends of the side rails that accept male brackets located at the ends of the cross rails and the components simply drop together. The same drop together feature can be used to secure the center beam to the cross rails.
Conventionally, with either of the aforedescribed bed frames, the side rails are constructed of metal angle irons which are L-shaped and there are legs that extend downwardly at each corner of the bed frame from the cross rails to contact the floor in order to support the weight imposed on the bed frame by the presence of the box spring, mattress and, of course, an individual or individuals sleeping in the completed bed.
One of the difficulties, however, with the use of an L-shaped angle iron for the side rails is that the cross sectional profile of the L-shaped angle iron renders the member susceptible to a bending weakness, that is, for example, when the bed is slid along the floor, the leg supporting the side rail is dragged across the underlying floor and can cause the cross rail member and side rail to twist and the twisting action can damage an L-shaped angle iron member that is not particularly resistant to such twisting action. This is especially true when a foot gets caught in an obstruction on the floor or on loose carpet. The situation is exacerbated by the use of off-set casters on the legs since the off-set casters can transfer downward force into side to side force that causes the bed leg to twist.
In addition, there is a bending action that is created by downward force upon the inner horizontal flange of a L-shaped side rail by a cross member resting on or supported by the horizontal flange of the side rail and which tends to twist the L-shape into a downward V-shape and continued force tends to try to flatten that V-shape. Basically the L-shaped side rail angle iron will twist inwardly away from the vertical flange, that is, the distal end of the horizontal flange will twist away from the vertical flange in the downward direction by the load imposed on the horizontal flange of the L-shaped angle iron. Thus, the problem with the use of an L-shaped angle iron for a side rail is not limited to the possible bending caused by a leg being twisted by encountering a snag in a carpet as the leg extending downwardly from a cross rail connected to an L-shaped side rail is moved across that carpet but also simply by the weight of the load imposed on the horizontal flange of the L-shaped side rail to twist the angle iron.
Another difficulty with the use of L-shaped angle irons for the side rails is in the connection of the legs to the side rails in making up the bed frame. That connection needs to be a strong connection for the integrity of the overall bed frame, however, with L-shaped angle irons, the strength of that connection is inherently compromised.
The typical conventional bed frame interfaces with a mattress and box spring by containing the side to side movement within the vertical flanges of the side rail and supports the weight through the horizontal flanges of the L-shaped side rails. The legs thus support the side rails off of the floor and, ideally, the legs would be positioned directly under the side rails at the intersection with the cross rails, giving maximum strength and support. For safety reasons, however, it is also desirable to recess the legs under the bed frame to keep them away from the users feet. Therefore, the legs are typically affixed in some fashion, to the cross rails inboard of the side rails. Such arrangement gives an indirect connection to the side rails and results in a weak connection between the leg and the side rails.
It would thus be advantageous to have side rails that are more resistant to twisting forces so that the bed frame maintains its integrity even when moving across a carpet or under heavy load. It would be further advantageous to have a connection between the legs and the side rails that is more robust and can withstand the twisting forces that are incurred on the connection between the legs and the side rails.